I guess its unethical of me to be fishing in water that has pike in it.
I frequently use 3 - 10 lb (mostly in 6-10 range) super lines and mono lines in waters that contain pike and some hogs as well. Usually targeting walleye and sometimes perch. Have landed some large pike on those weights of line.
If I was targeting large pike or pike in general the heavy stuff then out comes the heavy gear(20lb mono and 40 superlines).
Most people dont go into the heavy stuff so 8 - 15 pound is more than enough for pretty much all but the situations mentioned in above paragraph.